This invention relates to agricultural machines and, more particularly, to a harvesting machine, which during its operation may pick up stones or other non-frangible objects along with the crop being harvested.
As can be appreciated, the harvesting machines, such as, a combine, are susceptible to damage by non-frangible objects such as stones, or other hard objects (hereinafter referred to simply as "stones") that may be injested during the harvesting process. There have been various stone detecting and eliminating systems for protecting combines, as illustrated in various prior art patents. For example, there are a group of U. S. patents assigned to the Sperry Corporation which disclose various mechanisms for sensing the presence of a stone and for ejecting the stone to avoid its being introduced into the combine and destroying threshing mechanisms. The patents in question are: U.S. Pat. Nos. 4,275,546; 4,322,933; 4,335,563; 4,335,564; 4,335,565; and 4,353,199. As aforementioned, these patents disclose various detector systems for eliminating rocks from a combine wherein the sensing mechanism is located generally adjacent to an elevating crop conveyor mechanism.
While these various mechanisms have been generally successful, they are subject to the disadvantage that the trap door mechanisms employed may be open longer than desired, which would result in wasting of the crop. When the stones are detected, a trap door mechanism is opened and the stones and the associated harvested crop material are ejected from the combine.
Accordingly, there is a need for a mechanism which will provide for the rapid exit of the stones from the combine before they can damage the harvesting mechanism and will also facilitate closing of the trap door mechanism to minimize crop loss. It is also desirable that the trap door mechanism close in a manner to redirect material flow into the combine and preventing crop from being lodged between the trap doors.